Fernando Torres
Fernando Torres’ £50m moved from Liverpool to Chelsea in 2011 is the most expensive January transfer.Reuters

Juan Mata's move to Manchester United has become the second most expensive deal yet in the January transfer window, after the Red Devils agreed to pay Chelsea almost £40 million for the Spanish maestro.

But who else is in the top five all-time January signings? Well Mata has joined a fellow Spaniard, a Bosnian, a Uruguayan and an Englishmen. Perhaps unsurprisingly, Chelsea have been involved in the two biggest transfers - and three of them took place in the space of 48 hours.

Here is the top five list in full:

5. Luis Suarez, Ajax to Liverpool - £23m
To someone with no interest in football, Suarez's move from Ajax to Liverpool might not seem great value. The capricious forward cost £23m, enough to buy an entire team of top-class players 20 years ago, and during his time at Anfield he has proved a disciplinary nightmare, receiving lengthy suspensions for biting and racial abuse.

But what entertainment he's served up to the Anfield faithful when he's been on the pitch! At times Suarez has seemed to be carrying the entire Liverpool team, and his movement, ingenuity and speed have lit up the Premier League. Of all the top five transfers, he is the only unqualified success - in fact he may just be the best signing in the history of England's winter window.

4. Edin Dzeko, Wolfsburg to Manchester City - £27m
While Liverpool were busy raiding the Dutch league for Suarez, City were poaching in Germany, and eventually ended up spearing one of its biggest beasts - the towering Bosnian Edin Dzeko.

Dzeko has not had the impact in Manchester that Suarez has provided 30 miles down the road, but he is part of a far stronger squad with more competition for places. Given the amount of time he has spent on the bench at City, a return of 56 goals from 136 games isn't bad going - and he's avoided the kind of trouble that bedevilled former teammates Carlos Tevez and Mario Balotelli.

3. Andy Carroll, Newcastle to Liverpool - £35m
Liverpool's signing of Suarez was part of a chain reaction in which £100m changed hands in the space of two days and transformed the landscape of English football. Ultimately, only one of the three seismic signings paid off - the two giant fees proved grossly inflated.

While Suarez thrived at Anfield, Carroll, was a disaster - an albatross who symbolised the archaic approach of then manager Kenny Dalglish. Carroll, a gangly target man, would have been one of England's deadliest strikers in the 1980s. Unfortunately the game has now moved on, as Carroll demonstrated during his struggles at Anfield. He was eventually flogged to West Ham, and has fared little better in London.

2. Juan Mata, Chelsea to Manchester United - £38m
Manchester United usually keep their noses out of the January transfer window, and with good reason - the desperate scramble for bargains is inimical to their usual approach. But after the disastrous start to life under David Moyes, the Old Trafford bosses have finally made a major signing in January - and will be praying it comes off.

If Mata thrives at Old Trafford, he could galvanise United's season just as Mesut Ozil has invigorated Arsenal's, and provide a perfect replacement for Wayne Rooney, should he decide to leave in the summer. Should Mata fail, the pressure on Moyes will surely become untenable, and United will have to find another new manager. Mata is arguably the most naturally gifted player in the top five, but he will need steel as well as silk to cope with the pressure of his transfer.

1. Fernando Torres, Liverpool to Chelsea - £50m
Liverpool's twin purchase of Suarez and Carroll back in January 2011 was necessitated by the departure of Fernando Torres, who moved to Chelsea for a British-record £50m. As bargains go, it makes the Millennium Dome and the new Wembley look like value for money.

Torres was the best striker in the Premier League during his time at Liverpool, but that golden period is over. Although he has improved in the last two seasons, his figures are no match for his return in his first years at Anfield. Torres has scored just eight goals in 17 Premier League games this season, andt eight the previous campaign. Although he was a key player in Chelsea's Europa League victory last season, Torres must still go down as a flop at Stamford Bridge.